1. Field of the Invention
The present invention relates to a method of determining the angular position of a workpiece and positioning the latter relative to at least one tool, said workpiece having at least one set of teeth. The present invention also relates to an apparatus for carrying out this method. For the workpieces, the apparatus has a mounting support which is rotatably driven by a first drive mechanism. A reference shaft therewith is rotatably driven by a second drive mechanism. The first drive mechanism for the workpiece mounting support is provided with an angle measuring device that is connected to a computer.
2. Description of the Prior Art
For the subsequent machining of preliminarily toothed workpieces, for example following a hardening operation, it is necessary to position the workpiece in an exact angular position relative to the tool. This subsequent machining is effected, for example, by hobbing, such as with a hard metal peeler hobber, in a continuous hobbing or turning process. The tool and the workpiece rotate at a fixed and known gear ratio relative to one another. As a reference parameter for the angular position of the workpiece, the angular position of the tool spindle can be used in this case. The exact positioning of the workpiece relative to the tool is designated as centering. The workpiece and the tool must be positioned relative to one another in such a way that when the two sides or surfaces of the teeth of the workpiece are machined, in the ideal case, the same amount of material is removed from both sides. When the workpiece and the tool are not precisely aligned relative to one another, the teeth of the workpiece are not neatly or completely machined; i.e., more material is removed from one side of the teeth than from the other side. With the method of the aforementioned general type, the tool was up to now carefully manually moved into the preliminarily toothed gaps of the workpiece until the tool removed material from one of the surfaces. Subsequently, the tool was displaced in the direction of its axis and in the direction toward the opposite surface of the workpiece until the tool started to remove material from this other surface. The tool was then backed up by half of the amount of the displacement between the two engagement positions, so that the tool is disposed centrally between the two surfaces of the workpiece, and so that during the subsequent machining, approximately the same amount of material is removed from the two surfaces. This method is very complicated and imprecise, and is unsuitable for an automatically operating process. Other methods are also known for centering, according to which other relative movements between the tool and the workpiece are carried out. The common feature to all of these heretofore known methods is that the operator must observe the process very precisely, and must manually initiate the relative movement between the two engagement positions. Such processes cannot be automated.
An object of the present invention is to provide a method and apparatus of the aforementioned general types in such a way that the angular position of the workpieces can be simply and reliably determined automatically, and the workpiece can be automatically moved into the centering position; a first drive mechanism for the workpiece mounting support is provided with an angle measuring device that is connected to a computer.